In ice-cream making, the ingredients are kept below 0.0°C

Chapter 14, Problem 109P

(choose chapter or problem)

Get Unlimited Answers
QUESTION:

Problem 109P

In ice-cream making, the ingredients are kept below 0.0°C in an ice-salt bath, (a) Assuming that NaCl dissolves completely and forms an ideal solution, what mass of it is needed to lower the melting point of 5.5 kg of ice to −5.0°C? (b) Given the same assumptions as in part (a), what mass of CaCl2 is needed?

Questions & Answers

QUESTION:

Problem 109P

In ice-cream making, the ingredients are kept below 0.0°C in an ice-salt bath, (a) Assuming that NaCl dissolves completely and forms an ideal solution, what mass of it is needed to lower the melting point of 5.5 kg of ice to −5.0°C? (b) Given the same assumptions as in part (a), what mass of CaCl2 is needed?

ANSWER:

Solution 109P:

Step 1: (a)

Here, we are going to calculate the mass of NaCl is needed to lower the melting point of 5.5 kg of ice to −5.0°C.

Given that,

NaCl is a strong electrolyte solution. Thus, it dissociates into two particles.

Therefore,

The freezing point depression of NaCl is given by:

Given that,

= -5.0

 =1.86 /m

Therefore, the molality of NaCl is obtained as follows:

= 1.344 m

We Know that

1.34 mol/kg

Moles of NaCl = 7.392 mol

Similarly, the molar mass of NaCl = 58.44 g/mol

Therefore, the mass of NaCl needed = 7.392 mol 58.44 g/mol

                                        = 431.98 g


Add to cart


Study Tools You Might Need

Not The Solution You Need? Search for Your Answer Here:

×

Login

Login or Sign up for access to all of our study tools and educational content!

Forgot password?
Register Now

×

Register

Sign up for access to all content on our site!

Or login if you already have an account

×

Reset password

If you have an active account we’ll send you an e-mail for password recovery

Or login if you have your password back